1. Field of the Invention
The present invention relates to a system and method for monitoring soot build up in a diesel particulate filter of an internal combustion engine based on engine operating parameters.
2. Background Art
A number of strategies have been developed to reduce emissions for truck, automotive, and stationary engines used in power plants. In addition to controlling the basic combustion process using an electronic control module to balance trade-offs between performance and emissions, emission control devices are often placed in the exhaust stream to reduce or eliminate the byproducts of incomplete combustion. A particulate trap or filter is an emission control device placed in the exhaust stream to reduce particulate emissions, which are primarily carbon particles or soot. As more particulates accumulate in the filter or trap, the increasing restriction to exhaust flow results in a gradual increase in exhaust back pressure, i.e. the pressure within the exhaust upstream of the filter. If the trap is not properly maintained or if engine conditions prevent the trap from being regenerated, the exhaust back pressure may increase to a point which could jeopardize engine component life.
Diesel engine exhaust systems include particulate filters, catalyzed soot filters, and NOx adsorber catalysts that clean exhaust and reduce engine emissions. There is a need to regenerate and desulfate exhaust system components on a regular basis for efficient operation.
Regeneration of diesel particulate filters requires heating the filters to temperatures above 450° C. for a period depending on filter size, type, soot amount and regeneration conditions, for example, for a diesel truck highway operation engine operating normally, for about 10 minutes to over 1 hour.
The monitoring and control of a need for regeneration may be important but difficult to do. The monitoring of pressure in the diesel particulate filter has not been relied upon or easy to incorporate in the monitoring function in previously known systems.